The present paper focuses on the topic of Communities & Networks but it also covers some issues on Collaborative Enterprises, Collaborative Processes & Workspaces, and Business to Business Networks. It is based mainly on the Collective project Know Construct (COLL-CT-2004-500276) starting in March 2005. The project aims to develop a common internet-based platform for SMEs from the construction sector to provide an effective combination of two general functionalities: an innovative decision making support system regarding the products characteristics, applications and other consultancy services for SMEs' customers applying the ldquoweb enabled dialoguerdquo, and a system for SMEs to support an advanced form of co-operation through the creation of Knowledge Communities of SMEs in Construction Industry. The system supports the integration, management and reuse of the area specific knowledge via a common knowledge base. The system is intended to be used within the Associations to collect and exchange the business area specific knowledge among the members (SMEs) in a form of essential expertise, reachable anywhere, at any time.